While Programming Languages and Computer Languages seem to fit the bill, I understand the OP's hesitation in painting with too broad a brush.
This Wikipedia article on Comparison of programming languages lists all three of the desired categories in one breath:
The parentheses seems to nudge SQL and HTML out of the category of Programming Languages. Further, neither SQL nor HTML are listed in the central language comparison table (which comprises the bulk of the article). And with good reason: although these are standardized by committee, they are not procedural languages.
In particular, SQL is a non-procedural language. Different software houses have augmented SQL with a procedural side language that bear a different name (such as PL/SQL, in which the PL stands for "Procedural Language" citation).
To heighten the ambiguities, this Wiki article, List of Programming Languages by Type lists Java, C#, and SQL. While it does not explicitly name HTML, it does name other XML-based languages.
So it seems like Programming Languages are a hypernym for programming languages (like C#), query languages (like SQL), and markup languages (like HTML). But HTML and other markup languages seem on the periphery. (I could imagine a C# programmer asking a someone she'd just met what programming language he used. The answer, "HTML," would be met with a scoff. "That's not a real programming language," she might say.)
Consider their usage:
- Programming Languages implement algorithms to solve problems.
- Query languages implement set notation to retrieve data.
- Markup languages implement instructions telling a web page or printed page how to display its text. (HTML would be categorized as a specific type of XML, an eXtensible Markup Language citation). They are considered a metalanguage, that is, a language to describe other languages.
To answer the OP's question, it's completely understandable to say:
Alice and Bob put the website together from scratch, employing a variety of computer languages for the front-end, back-end and database-access portions.
However, it may be more clear to say
Alice and Bob put the website together from scratch, with Alice employing a variety of computer languages for the back-end and database-access portions, while Bob used HTML and CSS style sheets for the front end.